Resolution:

Make sure that the guidelines from the following article are applied:
/213958185

Configure the ChannelType value to HTTP at 'C:\Program Files (x86)\Parallels\PleskMigrationAgent\WINAgentMng.exe.config' on the source server and 'C:\Program Files (x86)\Parallels\Plesk\PMM\Migration\migrmng.exe.config' on the destination file.

Cause

The TCP connection between the servers is unstable without encapsulating to HTTP.